negative tests but pregnant?!

I'm showing all symptoms (morning sickness, breast tenderness, constipation, exhaustion/fatigue/28 days late, etc..) but yet every HPT has come back negative. I've been using First Response 3 minute tests. I've done the math and I would be 8 weeks pregnant but I'm curious as to why the HPT's have all come back negative. I have a doctors appointment on wednesday but I was really hoping to bring along a positive test (or a picture of one at least). I have a family history of PCOS and my mother could never yield a positive HPT even when she was 4 months along. I'm kind of worried because my family also has a high history of miscarriages, so I'm wondering if it's somewhat common (even in the slightest measure) that the hormones haven't made it into my urine because of luck or family history and I'm not crazy thinking I'm pregnant?!

my mom is so sure I'm pregnant, my husband thinks I might be insane.
I don't know what to think!

I got my period Oct. 19th for five days had cramps around the fourth for five days after no period for November or December. I also suffer from PCOS. home preg. test negative. GYN urine test was negative. According to the charts I would be around 7 weeks pregnant. My nipples have been bothering me for over three weeks. like in the milk duct they feel fuller and I know this may be TMI but I also have more vaginal secretions. I eat a lot more I am confused but something tells me to trust my instincts. I keep eating...like a cow. I hate it so much I have hunger pains like every hr or two. I try to fight it but cooking comes to mind like pasta with beef and tomato sauce with a glass of ginger ale. Or sometimes I eat in my sleep only happened three times. I lost so much weight only to gain 25 lbs in two months! like, are you kidding? And no vomiting. Nausea sometimes now I don't have that. just the n****e tingling constant especially after eating. I hear the hormone imbalance makes it difficult to detect HCG

Missed my period from November (lmp 22-10-2011). HPT show neg. am i Pregnant? my medical history==Ofter my Doctor give me to take Metformin hydrochloride 500 2 times. star this tablet from septmber 2011, ofter that my period come proper date on oct 22, but ofter october i dont have any period still now, befor i was suffering from a heavy menstrual bleeding last 2 years, that time i take birth control pill to regguler it. but i want a baby, so i go my doctor and he prescribe me glycomet. my all hormon level are normal. but he find me diabetic type 2 (Oral Glucose Tolerance Test)result are giving here == Fasting blood glucose level 84;1 hour: 140;ofter 2 hour: 135. . Lh and tsh are normal. am 35 +